'Bites of Knowledge': Ticks and Tick-Borne Pathogens Unveiled Through a Citizen Science Programme in Northern Spain

We present the findings of a citizen science project conducted in the Autonomous Region of Aragón (northern Spain), which engaged rural schoolchildren, wildlife rangers, hunters, and members of the general public.

Over the course of one year (April 2022-April 2023; three months for the schoolchildren), participants collected a total of 913 ticks (98.8% adult specimens) representing 13 species from across the region. The contributions included 373 ticks collected by schoolchildren, 319 by hunters, 108 by rangers, 91 by other volunteers, and 22 by the research team. Of these, 54 ticks were gathered from vegetation, 422 from wildlife (spanning nine animal species), 362 from pets, 44 from humans, and 30 from livestock.

Species identified were Rhipicephalus sanguineus s.l., Rhipicephalus sanguineus s.s., Rhipicephalus pusillus, Rhipicephalus bursa, Dermacentor marginatus, Ixodes hexagonus, Ixodes ricinus, Ixodes frontalis, Haemaphysalis punctata, Haemaphysalis sulcata, Haemaphysalis inermis, Hyalomma marginatum, and Hyalomma lusitanicum. DNA of a subset of 349 individual ticks was extracted and the presence of Rickettsia spp., Anaplasmataceae, and Borrelia burgdorferi sensu lato (the latter, only in Ixodes spp.) was analysed either individually (n = 62) or in pools containing 2-5 ticks (n = 79), of which 101 resulted positive: 88 were positive for Rickettsia spp., revealing the presence of Rickettsia massiliae, Rickettsia slovaca, Rickettsia conorii subsp. raoultii, Rickettsia aeschlimannii, Rickettsia hoogstraalii, Rickettsia helvetica, and Candidatus Rickettsia barbariae; 34 for Anaplasmataceae (both Ehrlichia spp. and Anaplasma spp., but in many cases was identified as endosymbionts); and three for B. burgdorferi s.l., with only one readable sequence (Borrelia valaisiana). Pathogens detected in ticks from humans included R. massiliae (n = 3), R. conorii raoultii, R. aeschlimannii and Ca. R. barbariae.

This study identified previously unreported tick-host-pathogen associations and contributed to raising awareness about the public health significance of ticks and strategies for their prevention.